Altered protein expression at early-stage rat hepatic neoplasia

Abstract

Protein expression patterns were analyzed in a rat model of hepatic neoplasia to detect changes reflecting biological mechanism or potential therapeutic targets. The rat resistant hepatocyte model of carcinogenesis was studied, with a focus on the earliest preneoplastic lesion visible in the liver, the preneoplastic hyperplastic nodule. Expression differences were shown by two-dimensional polyacrylamide gel electrophoresis and image analysis. Polypeptide masses were measured by peptide mass fingerprinting using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) and their sequences were obtained by tandem mass spectrometry. Alterations in expression of cytoskeletal and functional proteins were demonstrated, consistent with biological changes known to occur in the preneoplastic cells. Of particular interest was the differential expression of a serine protease inhibitor (serpin) with a role implicated in angiogenesis. Serpin, implicated in the inhibition of angiogenesis, is present in normal liver but has greatly reduced expression at the preneoplastic stage of liver cancer development. Immunofluorescence microscopy with antibodies to this serpin, kallistatin, supports the proteomic identification. Immunofluorescence microscopy with antibodies to the blood vessel marker von Willebrand factor provides evidence for neovascularization in the liver containing multiple preneoplastic nodules. These observations suggest that at an early stage of liver carcinogenesis reduction or loss of angiogenesis inhibitors may contribute to initiation of neoangiogenesis. A number of other identified proteins known to be associated with hepatomas are also present at early-stage neoplasia.

Integrated Glycoproteomics Demonstrates Fucosylated Serum Paraoxonase 1 Alterations in Small Cell Lung Cancer

“…The gene transfer of SERPINA4 was also found to suppress angiogenesis and metastasis in a hepatocellular carcinoma mouse model (30, 31) and in a gastric cancer mouse model (32). The decreased levels of SERPINA4 have also been reported in hepatocellular carcinoma tissue samples compared with normal liver tissue samples as indicated by two dimensional gel electrophoresis with proteomics analysis (33). Our data indicate a mild increase of SERPINA4 protein levels in SCLC samples and a more prominent increase of the fucosylated SERPINA4 form.…”

Protection Effect of Kallistatin on Carbon Tetrachloride-Induced Liver Fibrosis in Rats via Antioxidative Stress

“…Recent findings have indicated that kallistatin may play an important role in the protection against oxidative stress-induced inflammatory responses and organ damage. In a highly reproducible rat resistant hepatocyte model, kallistatin was not detectable or at very low levels in nodule tissue compared with normal liver by proteomics study [26]. A significantly reduced kallistatin level was seen in plasma samples from patients with chronic, severe liver disease [27], suggesting that kallistatin is produced mostly in the liver and can be consumed during inflammation in the liver.…”

Isolation and Preliminary Characterization of Herpes Simplex Virus 1 Primary Enveloped Virions from the Perinuclear Space

“…The strip was focused in an IPGphor isoelectric focusing system (GE Healthcare Biosciences AB). The proteins were diffused into the strip using active rehydration, and isoelectric focusing occurred overnight with a total voltage-hours of approximately 15 kV ⅐ h. The isoelectric focusing gel strips were rehydrated, equilibrated, and stained as previously described (20). The strip was overlaid on a 13% SDS-PAGE gel and was run until the dye front reached the bottom of the gel.…”